obtained in the Indian Seas. 251 



the distal ends of merus aud carpjis. The clielipcds of the 

 female are ranch more slender and shorter than those of the 

 male. Both clielipcds of the male are approximately equally 

 enlarged (right palm possibly slightly more dilated than the 

 left) . 



Of species hitherto described this one comes nearest 

 Diptrjchus uncifer (A. M.-Edu'ards) and D. politics (Hender- 

 son). The new species differs from the former in having a 

 sliorter rostrum aud still shorter antenual acicle ; mcrns of 

 cheliped smooth on its under surface, and no sharp tubercle 

 on under surface of ischium ; merus and carpus armed 

 distally; fingers entirely different. It differs from Z>. ^o/i/w^ 

 in the rostrum being much shorter and the acicle still more 

 so; carapace broader than long; fingers different. This 

 species can be at once distinguished by the form of the 

 fingers, size of rostrum and antenual aciele, and the carapace 

 being broader than long. 



The telson and caudal swimraerets of the females of this 

 genus are not so acutely flexed on the preceding segments 

 or so closely applied to them as in the males. 



Figures of both the male aud female, the latter clinging 

 to a species of Virgularia, will appear in "Illustrations of 

 the Zoology of R.I.M.S. ' Investigator.'" 



BRACHYURA. 



O X Y R H Y X C H A. 



Fam. Maiidge. 



Cyrtomaia Goodridgei, McArdle. 



Cyrtomaia Goodridqei, McArdle, Ann. & Mag. Nat. Hist. ser. 7, 

 vol. vi., Nov. 1900, p. 472 ; 111. Zool. Invest, pi. lix. figs. 1, 1 a, 1 b, 

 & \c. 



Of this species, described by McArdle from a single large 

 male specimen, this season three more specimens — an adult 

 and a young male and an egg-laden female — were obtained. 



Dimorphism in the male. — The adult male was caught at 

 Sta. 332, south-east of South Andaman Island, 279 fathoms. 

 It is somewhat smaller than McArdle's specimen, but it 

 presents this very striking and curious difference — its 

 chelipeds are in all joints, but especially the distal extre- 

 mities of the palms, very much enlarged and inflated. In 

 the general arrangement of the spines on the chelipeds both 

 specimens agree, and the gape (about 45°) is similar in both. 

 The hiatus, however, left at the base of the fingers wheu 

 closed is in the enlarged chelipeds much wider. The fingers 



18* 



